1. Field of the Invention
This invention comprises a two-sided grab bucket comprising a U-shaped scoop carrier and two scoops, which are provided with crosspieces, which are welded to the inside surfaces of the upper edge portions of the side walls of the scoops and are pivoted to the legs of the scoop carrier on two spaced apart parallel axes, actuating levers, which are welded to the crosspieces, and a transversely extending hydraulic piston-cylinder unit, which is pivoted to and connects the free ends of said levers.
2. Description of the Prior Art
A two-sided grab bucket of that kind, comprising a transversely extending hydraulic piston-cylinder unit, is known from Published German Application No. 30 37 866 which corresponds to U.S. Pat. No. 4,405,167 granted Sept. 20, 1983 to A. Kinshoffer.
In an open position, grab buckets should have a mouth clearance which is as small as possible so that they can be used also in narrow spaces, such as containers, trenches or the like. To ensure that the grab buckets have the largest possible capacity, the spacing of the pivotal axes for the scoops must be minimized. A grab bucket having a transverse piston-cylinder unit must meet a number of requirements, which can be fulfilled only with difficulty if the grab bucket should have the largest possible capacity, the smallest possible mouth clearance and the smallest possible width. In order to minimize the width of the grab bucket, i.e., the spacing of the side walls of the scoops, the pivots of the piston-cylinder unit must lie in a vertical plane because parts of the opening and closing mechanism cannot move past each other unless the width is increased in an undesirable manner.
In order to ensure that the scoops can be opened to an angle of about 80.degree., as is required for a satisfactory function, the spacing of the pivotal axes of the scoops must be as large as possible. But a large spacing of the pivotal axes will involve a smaller capacity of the grab bucket, which will not have an adequate capacity unless the pivotal axes are only closely spaced apart.
To provide a grab bucket having a small overall height, the lengths of the actuating levers must be minimized so that the scoops can be opened to the largest possible mouth clearance by a small displacement of the pisto-cylinder unit. It must be borne in mind that the piston-cylinder unit when it is in its lowermost position must not collide with the preferably tubular members used to stiffen and/or to mount the scoops.
The two-sided grab bucket disclosed in the aforesaid U.S. Pat. No. 4,405,167 cannot be as compact as may be desired because it must be ensured that the cylinders will not strike against the sleeves provided for stiffening and mounting the scoops during the closing of the scoops.